I did a long comparison with the Empyrean's and LCD-4z's in a review I did. I had the Burson Conductor 3XR at the time. The Burson 3XR and Soloist 3XP both really excel with warmer headphones in my opinion. I just didn't like either of them with the Susvara's, but that is another story.
The Empyrean and LCD-4z headphones have very similar bass and midrange performance. The difference to my ears was that the LCD-4z's offered better resolution and clarity throughout the frequency spectrum. Bass is tighter with better punch on the LCD-4z's. The Emyprean's has more bass but is looser and less defined. The midrange is cleaner and not as thick on the LCD-4z's as it is on the Empyrean's. The Emyprean's at the time had better treble clarity and it extended further. This is one area the updates on the LCD-4z's have improved upon. The treble frequency is a lot smoother now on the LCD-4z's.
Overall, the Empyrean's are just a step behind the LCD-4z's in presenting a detailed presentation. They also fall behind is resolve and transparency when compared to headphones like the HEKse and Diana Phi's and V2's. The updated LCD-4z's widens the gap in sound even more to my ears. Now the LCD-4z's sound even more balanced and the upper midrange/lower treble dip is not even audible to my ears.
The Empyrean's have a smoother, lush delivery that is very musical and easy to enjoy. The LCD-4z's are not a smooth because it has better technicalities and sounds a little more open in comparison. If you can get a listen to the LCD-4z's you should. If for not other reason that to satisfy your curiosity
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